Drag eliminator for ships



Ot. 20, I931. s. AITKEN 1,827,806

DRAG ELIMI NATOR FOR SHIPS Filed Aug. 20. 1929 V Patented am, 1 931;

warren-stares sin/1on1. AITKEN, or n-As'r cannon, NEW JEBS-EY,@;A$SIG1\IOR no JJRAenLIMr a-roa COMPANY, me, on NEW YORK, N. .,n*co1aronar1on or DELAWARE Dane ELIMINATO R.ronssnrrsq Applicationfiled. August 20.1529. semi 1%. 387,229.

This invention covers improvements in boats or ships for the purpose of'elirninating drag an'd thereby decreasing the power required for obtaining any desired speed, or

fifor "increasing speed without increasing "by way of illustration what is now considered power. r

The invention pertains especially tojthose portions of the ship whichare below water" level-atthe stern in the neighborhood of the 1B propeller.

It has been customary to leave broad coniparatiyely flat surfaces across the stern frame and across the rear of the rudder. Ihave found that by reshaping those surfaces subg.

stantial gain in speed is secured without additional power, and the'object of this i.nVen'-- tion is to disclose the improvements which have brought about those results." Further and other objectsand advantages will be apparent from the specification and claims, and from the drawings which show thepreferred form ofthe invention. Figure 1 shows a side view of arudder and of a'portion of a ships hull to'which myim provements have been applied.-

Fig. 2 is a cross-section on line 22 of;

The hull of the ship is designated 10, the 1 propeller 12, and the rudder 14. To the rudder I rivet the rearwardly projecting plates 16 which are riveted together at their rearmost edges at 18 to form the V-shaped streamline cross-section shown in Fig. 2. In like manner plates 20 are secured to the sides of the stern frame above and in front of the pro pellerto produce the streamline cross-section as indicated'in Fig. 3. The stern frame'below and in front of the propeller is streamlined by platesQQ, asin Fig. 4. The stern'fralne to the 'rearof the upper part of thepropeller is equipped. With forwardly projecting plates- 24 to provide a- V-shaped cross-section similar to Fig. 3. Theforward edge 26 of the rudder,

in the'rear of thepmpeller is streanilined'in w an ew h al pra tice. 7 1

Itis to be unde stood that the'inventionjs embodiment" herein described,fbut.ma'y be used .in other ways without departureflfromits spirit as defined by the following claims. ian 1113 Said propeller," and means. attached to said wards. said Theimprovementsdescribed abovejhave f beenapplied to several ships and in every case dragihas' been eliminated to such an extent i that increased speed'has beenobtained'with- .o'ut increasedp'ower. l

"1.1 .11 a h a r pe er, a1 5 m frame F having upright portions thereof positioned only forje a'nd aft ofysaidflpropeller whereby the bottomofthe frame is entirely open below having uprightj portions 'thereoi positioned" Y i only r le a ndfaftof said propeller wherebyf 11. i

said propeller:andnieans attached to said" frame for providing said portions W1tl1 jecting towards as de'scribed. e p 7 1 .-*Th i"in e itib et o h. i im 2 iil which said edgesare'formed of plates riveted id fr m per ien' 'a Pr i cting. -f from; i f

I 4. "In a ship, a stern'frame'havingl on open bottom whereby the water has unimpeded access to the propeller, a rudder, and means shaped edges tapering toward the stern of the ship, substantially as described] 7 .saiidpr'opeller substantially] 5. The invention set forth in"c1aim a} in attachedto said frame andrudderforproe 1 viding saidframe and said ru'dder with V:

which saidedges are formed ofplatesriveted ffrom. a

" 6;In a ship, apropeller; a stern frame comprising an u per; inverted U-shaped member having. its vertical portions fore and aft of the propellerfabovethe'hulo thereof,

and a lower open-.bottomimember consisting" to said-frame portions'and projecting there- [foo l v s r 1,827,806

only of a single portion inclined downwardly and forwardly from a point adjacent said hub to the keel of said ship and means for streamlining said frame members, toward said pro-' 5 peller, substantially as described. 7 x

7. A stern frame for ships,.oomprising a downwardly open arch-shaped'uppermember having streamlined fore and aft members :providing space for propeller blades", and

p 10 havinga streamlined lower memberarranged below and forwardo-f thepropeller to, leave the frame open for unimpeded access of Water to the propeller rotating on an" axis located between said upper and lower mem- 15 bers. v w

8. The invention setforth in claim 7 in which said lower frame member extends 'downwardlya'nd forwardly from a pointfadja'cent the propellerhub'and away from the 9 line, of rotation ofthe propeller blades;

9.111 a ship, a propeller, a rudder, and a stern frame having astreamlined lower-portion inclined downwardly and forwardly from the propeller hub, thereby permitting unimpeded' access'of waterlto' the propeller between said-lowerframe:portionand said 7 rudden, ,1 1' 101111 a ship, a propeller, astern frame having an upper streamlined portion aft of 0 the upperpart of the propellerand term-inating above the propelleryaizis and a, rudder ent'i relyvsupported by said upper f ame portionand'havingthe forward streamlined edge thereof located below said sup portingstream- 35 lined frameportion'. r

11; A stern frame for ships, comprisingfa downwardly open arch-shaped upper member having streamlined-fore andt aftimembers 'providingspaceffor propeller" blades, and: o n

: 0 having'a streamlined-lower'memb-er arranged to leave the frameopen for unimpeded access 'ofwater to a propellerf rotating on an axis located betweensaid upper andflowe'r Inembers, inpcombination with a rudder entirely e supported by said upper frame portion and having a forward streamlinediedge thereof located belows'aid supporting frame "port-ion, thereby providing streamlined frameand rudder edges fore and aft of said propeller,

5 ithno part of said uppermember below the propelleriaxis. 'f I l 12. In a ship, a sternframe, and: means for providing saidframe with a rearwardly pro-. jecting V-shaped edge, said means compris- 5 ing plates riveted tosaid frame portions and projecting therefrom. I i E In testimony. whereof I hereto aflix my signature", j SAMUEL AITKEN; 60, 7 f I 

